In pointing out the paradoxes of modern advances, James Reason1 retells the story of the French cavalry in the 1415 battle of Agincourt: Bedecked in the latest armor, the French forces seemed invincible. The British, however, succeeded in knocking the French cavalry from their horses, leaving the French soldiers in their heavy, clumsy armor virtually helpless on the ground. The ensuing slaughter of the French troops was unexpected but, thanks to their state-of-the-art armor, inevitable. The French learned the hard way that technological advances designed to improve safety can paradoxically increase risk. New technology increases complexity, tends to make interactions opaque, and introduces new modes of failure that did not exist in the original system.1,2